U.S. patent application number 15/333622 was filed with the patent office on 2017-05-04 for wide bandgap junction barrier schottky diode with silicon bypass.
The applicant listed for this patent is United Silicon Carbide, Inc.. Invention is credited to Anup Bhalla.
Application Number | 20170125394 15/333622 |
Document ID | / |
Family ID | 58635154 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170125394 |
Kind Code |
A1 |
Bhalla; Anup |
May 4, 2017 |
Wide Bandgap Junction Barrier Schottky Diode With Silicon
Bypass
Abstract
A silicon surge bypass diode is co-packaged with a high bandgap
junction barrier Schottky diode. The co-packaged diodes may be used
in a power circuits such as power factor correction circuits,
converters, inverters circuit, motor drives, and protection
circuits, for example. The high bandgap diode may be made of
silicon carbide, gallium nitride, aluminum nitride, aluminum
gallium nitride, and/or diamond, for example. The high bandgap
diode may be formed by diode connecting a transistor, such as a
high-electron-mobility transistor (HEMT). The high bandgap diode
may be much smaller than the silicon diode. The package may have a
common terminal for the diode cathodes, and separate terminals for
the anodes of each diode.
Inventors: |
Bhalla; Anup; (Princeton
Junction, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
United Silicon Carbide, Inc. |
Monmouth Junction |
NJ |
US |
|
|
Family ID: |
58635154 |
Appl. No.: |
15/333622 |
Filed: |
October 25, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62248010 |
Oct 29, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02M 1/4225 20130101;
H02M 1/32 20130101; Y02B 70/10 20130101; H01L 25/072 20130101; H01L
2224/48247 20130101; Y02B 70/126 20130101; H01L 25/18 20130101;
H01L 23/62 20130101; H01L 27/0255 20130101; Y02B 70/1483
20130101 |
International
Class: |
H01L 25/18 20060101
H01L025/18; H01L 23/60 20060101 H01L023/60; H01L 27/02 20060101
H01L027/02 |
Claims
1. A device, comprising: a junction barrier Schottky (JBS) diode
made from a wide bandgap material a silicon diode; and a common
package comprising a first terminal and a second terminal, where:
the JBS diode and the silicon diode are mounted in the common
package; the first terminal is connected to the anode of the JBS
diode; the second terminal is connected to the anode of the silicon
diode; and the first and second terminals are separate.
2. The device of claim 1 where the silicon diode is at least
1.5.times. larger than the JBS diode in die area.
3. The device of claim 2, further where: the common package
comprise a third terminal; and the third terminal is connected to
the cathode of the JBS diode and to the cathode of the silicon
diode.
4. The device of claim 3, wherein the JBS diode is made of silicon
carbide, gallium nitride, aluminum nitride, aluminum gallium
nitride, and/or diamond.
5. The device of claim 4, wherein the JBS diode is a
diode-connected transistor.
6. The device of claim 5, wherein the JBS diode is bonded to a
direct bond copper (DBC) ceramic plate, and the DBC ceramic plate
is bonded to the common package.
7. The device of claim 6, wherein the JBS diode is a
diode-connected high-electron-mobility transistor (HEMT).
8. The device of claim 4, wherein the common package is a TO-220 or
TO-247 package.
9. A power circuit comprising the device of claim 4.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/248,010, filed on Oct. 29, 2015, entitled "Wide
Bandgap Junction Barrier Schottky Diode with Silicon Surge Bypass",
the content of which is hereby incorporated by reference in its
entirety.
FIELD OF THE DISCLOSURE
[0002] This disclosure is in the field of junction barrier Schottky
(JBS) diodes and circuits incorporating JBS diodes. Devices
integrating wide bandgap JBS diodes and silicon components are
disclosed.
BACKGROUND
[0003] High-current and high voltage devices made from wide bandgap
materials such as silicon carbide (SiC), gallium nitride (GaN),
aluminum nitride (AlN), aluminum gallium nitride (AlGaN), and
diamond are useful in power electronic circuits, such as power
factor correction (PFC) devices, DC-DC converters, DC-AC inverters,
overcurrent and overvoltage protection circuits, and motor
drives.
SUMMARY OF THE INVENTION
[0004] A silicon surge bypass diode is co-packaged with a high
bandgap junction barrier Schottky diode. The co-packaged diodes may
be used in power circuits such as power factor correction circuits,
converters, inverters circuit, motor drives, and protection
circuits, for example. The high bandgap diode may be made of
silicon carbide, gallium nitride, aluminum nitride, aluminum
gallium nitride, and/or diamond, for example. The high bandgap
diode may be formed by diode connecting a transistor, such as a
high-electron-mobility transistor (HEMT). The high bandgap diode
may be much smaller than the silicon diode. The package may have a
common terminal for the diode cathodes, and separate terminals for
the anodes of each diode.
[0005] This summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the detailed description. This summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used to limit the scope of the claimed
subject matter. Furthermore, the claimed subject matter is not
limited to limitations that solve any or all disadvantages noted in
any part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The summary, as well as the following detailed description,
is further understood when read in conjunction with the appended
drawings. For the purpose of illustrating the invention, there are
shown in the drawings exemplary embodiments of the invention;
however, the invention is not limited to the specific methods,
compositions, and devices disclosed.
[0007] FIG. 1 is a schematic of an example of a simple circuit
where a boost diode is used in conjunction with a surge bypass
diode.
[0008] FIG. 2 is a schematic of an example of a more complex
circuit where a boost diode is used in conjunction with a surge
bypass diode.
[0009] FIG. 3 is a graph of voltage and current over time for
example circuits.
[0010] FIG. 4 shows a schematic of an example device including two
diodes and a view of the diodes placed in a package.
[0011] FIG. 5 shows a view of an example device including a lateral
diode co-packaged with another diode.
DETAILED DESCRIPTION
[0012] A silicon surge bypass diode is co-packaged with a high
bandgap junction barrier Schottky diode. The co-packaged diodes may
be used in power circuits such as power factor correction circuits,
converters, inverters circuit, motor drives, and protection
circuits, for example. The high bandgap diode may be made of
silicon carbide, gallium nitride, aluminum nitride, aluminum
gallium nitride, and/or diamond, for example. The high bandgap
diode may be formed by diode connecting a transistor, such as a
high-electron-mobility transistor (HEMT). The high bandgap diode
may be much smaller than the silicon diode in physical size and/or
surge capacitor. The package may have a common terminal for the
diode cathodes, and separate terminals for the anodes of each
diode.
[0013] In a power factor or boost converter circuit, for example,
the co-packaged high bandgap diode may be small compared to the
silicon diode. This is due to the high bandgap diode not having to
bear a large surge current. This has several advantages. A smaller
physical size means both lower cost and lower switching
capacitance. The latter means, in turn, that the circuit may
operate faster and/or produce less waste heat. Packaging the
devices together also uses less space. Further, a common-cathode
configuration allows for the use of a three-terminal package.
[0014] FIG. 1 is a schematic of an example of a simple circuit 100
where a boost diode D100 is used in conjunction with a surge bypass
diode D102. This circuit 100 is a high frequency boost converter,
such as is commonly used in power factor correction, e.g., for
power supplies over 60 W. Power enters at terminal T100 and is
boosted through inductor L100 by the switching of transistor M100.
D102 is a surge bypass diode and made be made from a material such
as silicon. D100 is a boost diode which feeds output terminal T102.
D100 may be a junction barrier Schottky (JBS) diode made from a
wide bandgap material. A JBS diode may be preferred since such
diodes do not lead to reverse recovery losses in the transistor
M100. A low capacitance in the boost diode D100 is beneficial for
system efficiency, since it leads to lower turn-on losses in the
transistor M100. JBS diodes with voltage ratings above 600V may be
made from wide bandgap materials such as SiC, GaN, AlN, and
diamond, among others, which allow for low on-state voltage drops
and low capacitances with small die sizes, due to the excellent
material properties of these wide bandgap semiconductors.
[0015] However, if an event occurs that forces a large surge
current through the wide bandgap diode D100, it is prone to thermal
destruction due to its small die size. Since Si die are much
cheaper, and have a lower junction drop, a large die silicon bypass
diode D102 can be used to sustain considerable surge current
without damage.
[0016] FIG. 2 is a schematic of an example of a more complex
circuit 200 where a wide bandgap diode is used in conjunction with
a silicon surge bypass diode. Here the input across terminals T1
and T2 is fed to a diode rectifier bridge consisting of diodes D1,
D2, D3, and D4. The negative output of the bridge, at the anodes of
D3 and D4, serves as the common connection for the output circuit,
which is connected to terminal T4. The positive output of the
bridge, at the cathodes of D1 and D2, is fed to the anode of a
bypass diode D5, capacitor C2, and resistor R2. The cathode of D5
is connected to the circuit output terminal T3, which is loaded by
a resistor R1 in series with a capacitor C1 which is connected to
circuit common. The boost pathway feeds through resistor R2 through
an inductor L1 to switch to common S1, and to the anode of a boost
diode D6. In parallel with switch S1 is a diode D7. Diode D7 has
its cathode connected to L1 and its anode connected to common.
[0017] FIG. 3 is a graph of voltage and current over time for
example circuits with and without a bypass diode. Consider, for
example, the effect of a surge on a circuit such that the circuit
of FIG. 2 under the following conditions: the voltage across output
capacitor is at zero, and the input AC line voltage across input
terminals T1 and T2 is abruptly turned on at the peak of the
voltage cycle. In FIG. 3, curve 301 is the AC line voltage, which
is switched on at time zero. If D5 is not present, a large pulsed
current 302 flows in the boost diode D6. For the component values
shown in FIG. 2, the peak of the boost diode current 302 may be 100
amperes.
[0018] If instead bypass diode D5 is in place, a much lower current
304 is seen through the boost diode D6. Most of the surge is born
by the bypass diode D5 as current 303. The peak current through the
boost diode D6 drops to under 40 amperes. This dramatically lowers
the amount of energy absorbed by the die of D6. This means that a
much smaller device may be used, which greatly reduces the cost of
the device. The lower capacitance of the smaller wide bandgap diode
die further improves circuit performance. The surge current in the
bypass diode is large. However, this component may be a less costly
silicon diode, and therefore a physically larger die without
significantly impacting cost. The die size area of the bypass diode
D5 may be, for example, 1.5 times larger than the die size area of
the boost diode D6, or larger. Similarly, the surge current
capacity of the bypass diode D5 may be 1.5 times the capacity of
the boost diode, or more, even when the two diodes are comparable
in physical size.
[0019] The inventors observe that in circuits such as those shown
in FIGS. 1 and 2 that the surge bypass silicon diode and the wide
bandgap diode share a common cathode. Therefore these components
may be mounted in a common package as die on a common pad.
[0020] FIG. 4 shows a schematic 405 of an example device that
includes a wide bandgap diode and a silicon diode, along with a
view of the diodes placed in a package 404. The large silicon diode
401 is co-packaged with a small, wide bandgap JBS diode 403 on a
common paddle 406 of a three-leaded TO-220 package 404. The
cathodes of the silicon diode 401 and the JBS diode 403 are bonded
to the common paddle 406. The silicon diode 401 may be a relatively
large device and be used, for example, as a bypass diode in a PFC
circuit. The wide bandgap JBS diode 403 may be used, for example,
as a boost diode in a PFC circuit. Placing both devices into the
same housing in the shown configuration saves space and cost, by
eliminating one package.
[0021] The anode of the silicon diode 401 is brought out to pin 1
of the package. The anode of the JBS diode 403 is brought out to
pin 3 of the package. The common paddle die pad area 406 may be
made of copper. The die pad area 406 is connected to the common
center pin 2 and to an exposed heat sink tab 402. The die pad area
406 is encapsulated to protect the diodes 401 and 403.
[0022] It will be appreciated that many similar configurations are
possible. For example, other packages may be used, such as other
through-hole packages like the TO-247 and/or surface mount
packages. The common cathode configuration of the silicon die and
the wide bandgap die is preferred. Any pin configuration may be
used as long as the two anodes are provided separately.
[0023] FIG. 5 shows a view of an example device 504 with a small
lateral diode 507 co-packaged with a large silicon diode 501. The
lateral diode 507 has an anode pad 50 and a cathode pad 505 on its
top surface. The lateral diode 507 is a wide bandgap device that
may be used, for example, as a boost diode in a PFC circuit. The
lateral diode 507 may be, for example, a GaN HEMT-like lateral
Schottky diode. Lateral diode 507 may be mounted on a direct bond
copper (DBC) ceramic plate 503 that is thermally conductive but
electrically insulating. Plate 503 may in turn be mounted on the
common die pad 506. By this method, lateral diode 507 may be
electrically isolated from the common die pad 506 but thermally
connected to the common die pad 506. The anode 510 of the lateral
diode 507 is connected to pin 3 of the package. The cathode 505 of
the lateral diode 507 is connected to pin 2.
[0024] The silicon diode die 501 may be directly attached to the
package common copper die pad 506. The silicon diode 501 may be a
relatively large device that may be used, for example, as a bypass
diode in a PFC circuit. The anode of large silicon diode 501 is
connected to pin 1 of the package. The common die pad 502 and the
cathode of the lateral diode 507 are connected to the center pin 2
of the package, thus forming a common cathode with the silicon
diode.
[0025] Device 504 is depicted as being implemented in a TO-220
package, where tab 502 is connected to the common pin 2 and may
serve as a thermal heat sink connection. Further, device 504 is
depicted with a particular pin arrangement. It will be appreciated,
however, that the device could be implemented in a number of ways,
including using a variety of through-hole and surface mount
packages, as well as with a variety of pin configurations.
[0026] The present invention may be understood more readily by
reference to the following detailed description taken in connection
with the accompanying figures and examples, which form a part of
this disclosure. It is to be understood that this invention is not
limited to the specific devices, methods, applications, conditions
or parameters described and/or shown herein, and that the
terminology used herein is for the purpose of describing particular
embodiments by way of example only and is not intended to be
limiting of the claimed invention. Also, as used in the
specification including the appended claims, the singular forms
"a," "an," and "the" include the plural, and reference to a
particular numerical value includes at least that particular value,
unless the context clearly dictates otherwise. The term
"plurality", as used herein, means more than one. When a range of
values is expressed, another embodiment includes from the one
particular value and/or to the other particular value. Similarly,
when values are expressed as approximations, by use of the
antecedent "about," it will be understood that the particular value
forms another embodiment. All ranges are inclusive and
combinable.
[0027] It is to be appreciated that certain features of the
invention which are, for clarity, described herein in the context
of separate embodiments, may also be provided in combination in a
single embodiment. Conversely, various features of the invention
that are, for brevity, described in the context of a single
embodiment, may also be provided separately or in any
sub-combination. Further, references to values stated in ranges
include each and every value within that range.
[0028] In describing preferred embodiments of the subject matter of
the present disclosure, as illustrated in the figures, specific
terminology is employed for the sake of clarity. The claimed
subject matter, however, is not intended to be limited to the
specific terminology so selected, and it is to be understood that
each specific element includes all technical equivalents that
operate in a similar manner to accomplish a similar purpose. When
ranges are used herein for physical properties, such as chemical
properties in chemical formulae, all combinations, and
subcombinations of ranges for specific embodiments therein are
intended to be included
[0029] Those skilled in the art will appreciate that numerous
changes and modifications can be made to the preferred embodiments
of the invention and that such changes and modifications can be
made without departing from the spirit of the invention. It is,
therefore, intended that the appended claims cover all such
equivalent variations as fall within the true spirit and scope of
the invention.
* * * * *